The present invention relates to a device for supporting a standing worker in the least stressful position for the purpose of reducing back strain and fatigue, and minimizing swelling and discomfort in the lower legs.
Chairs and stands for reducing back strain and fatigue are well-known. Chairs that provide support at a user's posterior and knees are also well-known. Conveyor belts or assembly lines are not designed for seated employees, and conventional chairs will prevent employees from reaching their work without causing strain. Known chairs stands or leans do not support the body in the least stressful standing position, with the knees slightly bent and the pelvis maintained upright. Employees often use the stands like conventional chairs, which will prevent them from reaching their work.
Workers standing for prolonged periods of time and especially those performing forward reaches have heretofore not had adequate support to fully minimize back strain. To minimize back strain while standing, especially when reaching forward, it is important to have the knees slightly bent, the pelvis upright, and the back relatively straight. This position is considered the least stressful standing position by experts in preventing back injuries.
Back strain is common in conveyor or assembly line workers who perform reaching tasks. The strain is increased when the reach distance is greater, the object being lifted is heavier, or the reaching position is held for a longer period of time.
To determine the stress to the back from any type of reaching or lifting task, the bio-mechanical lifting equivalent, weight times distance, is used. The weights of the object and the parts of the body being lifted are multiplied by the distance between the area of greatest concentration of stress on the back and the farthest point of the reach. When reaching forward, a standing worker having no support for the pelvis and shins must lift more of their total body weight, thus increasing the strain to the back. Bending the torso forward and reaching with the arms fully extended can be equivalent to lifting as much as half of an individual's total body weight. It is therefore desireable to minimize forward bending of the torso, thereby decreasing the total body weight being lifted. By bending the knees and wedging the body upright between two vertical structures, the pelvis is maintained in an upright position, and forward bending of the torso is prevented. In order to keep the knees bent and the pelvis maintained in this position, it is essential to provide support to the shins and the buttocks. Standing with the knees slightly bent relaxes the muscles in the lower back, which also helps minimize back strain.
Another consideration is that prolonged standing, especially with little or no leg movement, can lead to swelling and discomfort in the lower legs and feet. To counteract this problem, it is important to minimize the amount of weight the legs must support. By wedging the body between two vertical structures that provide support to the shins and the buttocks, the total body weight supported by the legs is significantly reduced.
Thus it can be appreciated that a support stand is needed that supports the body in a least stressful position while standing. It can be further appreciated that a support stand is needed that easily and fully adjusts to the sizing requirements of each person, that is lightweight and easily transportable. The present invention solves these and other problems associated with support stands.